36 Pa. Stat. § 670-905
Any county may appropriate and expend moneys, and incur such indebtedness and issue bonds, or other obligations therefor, as may be necessary to pay all, or any portion of, the damages to property resulting from any widening or relocation made with the consent of the county, or to pay for the improvement and maintenance of any State highway or any public highway, including sidewalk construction, within its proper limits: Provided, That no improvement can be made to any State highways until the same has been submitted to and approved by the department: And provided further, That no county shall appropriate and expend any of such moneys for the improvement and maintenance of any public highway, other than a State highway or county road, where the highway is to be improved jointly by the township or borough or town or city and county, until and unless the supervisors or commissioners of the township, or council of the city or borough or town in which the highway proposed to be improved lies shall first petition the county commissioners of the county, representing that any highway or section thereof, lying within such township or borough or town or city, on which it is proposed that said money shall be expended, is in need of reconstruction or repair, and particularly describing said highway, and until and unless the said application has been submitted to and approved by the department: And provided further, That when the improvement and maintenance of any public highway in the county is desired by the county without the intervention of the township or borough or town or city, the commissioners of said county may make application for approval direct to the department.
36 P.S. § 670-905